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Contact Austria: AEE INTEC (www.aee-intec.at)

France: Tecsol (www.tecsol.fr)

Germany: Fraunhofer ISE (www.ise.fraunhofer.de)

Greece: CRES (www.cres.gr)

Italy: Small-Scale Solar Heating and EURAC (www.eurac.edu) University of Bergamo Cooling Systems (www.unibg.it)

Spain: Package Systems for Combined , Ikerlan (www.ikerlan.es) Domestic Hot Water Preparation and Space Heating

Industry partners: Standardized System Solutions CLIMATEWELL (www.climatewell.com) Fagor (www.fagor.com) Package Solutions on the Market SK Sonnenklima (www.sonnenklima.de) SOLution (www.sol-ution.com) SorTech (www.sortech.de) Solar thermal domestic hot water heating (DHW) DHW Further information: EURAC research – project coordinator & space heating Solar Combi Viale Druso/Drususallee 1 & space cooling Solar Combi+ I-39100 Bolzano/Bozen Tel. +39 0471 055610 Fax +39 0471 055699 February 2010 [email protected]

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Table of Contents

What is a Solar Combi Plus System? ...... 3 Most Promising Climatic Regions...... 4 Suitable Collector Technology ...... 6 Standard System Configurations ...... 9 Recommendations on System Design...... 11 Package System - Climatewell...... 14 Package System - SOLution ...... 16 Package System - SorTech ...... 18 Contact ...... 20

& cooling

Example: Green Lighthouse Copenhagen First CO 2-neutral building in Denmark Heat resource: 30 m² flat plate collector Heat rejection: Drycooler with spraying (RCS 08) Cooling: Fancoils, AHU Engineering and Realization: COWI / Solar A/S / SorTech AG

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What is a Solar Combi Plus System? Package System - SorTech Solar combi plus systems use heat from solar thermal Cooling and Heating collectors to provide heating in winter, cooling in summer and domestic hot water (DHW) all year round. The figure below Adsorption Chillers with 8 or 15 kW cooling capacity sketches the main components, which make up a typical SorTech AG develops, manufactures and distributes adsorption system: (i) the to provide the heat chillers in the small scale performance range. The chillers are usually backed up by an auxiliary heat source, (ii) a storage compact, highly efficient and noiseless. The electricity tank can either be installed on the hot side, as shown in the consumption of an ACS 08 is only 7 W – this is unmatched figure, on the cold side or on both, (iii) a domestic hot water worldwide. Driving temperature as low as 55°C is sufficient to preparation unit, (iv) the sorption chiller is fed with hot water drive the chillers. That’s why SorTech chillers are a perfect (70-100°C), (v) heat rejection at intermediate temperature match for solar-driven cooling. Furthermore, the machines can (30-40°C) to a (dry or wet) or another heat sink also be used for heating assistance with the integrated heat (e.g. a swimming pool), (vi) the cold distribution system (e.g. pump mode. a chilled ceiling, -coils or air handling units) and (vii) the As a contribution to the SolarCombi+ project efforts SorTech heat distribution (preferably a low temperature system). now offers auxiliary equipment to simplify planning and to facilitate installation and operation.

Hence, SorTech not only delivers adsorption chillers but also heat rejection systems, which are optimized for operation with the chillers and pump stations in different variations. Those

pump stations include all necessary infrastructure for M M

connecting the buffer store, heat rejection and cold distribution M

M system to the chiller. Additionally, SorTech assists you in

M E-2 E-4 M planning and design. SorTech chillers have been installed in Germany, Austria, Switzerland, Italy, Spain, France and Greece. The systems consist of different components in the heat rejection and cold distribution system. The chillers work reliably especially at varying temperatures.

Figure 1 - Typical setup of a solar combi plus system

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System Schematics

Most Promising Climatic Regions Solar combi plus systems are most suitable for buildings with both heating and cooling demand. This depends first of all on the climatic conditions. Figure 2 shows a map of the distribution of heating degree days in Europe. Heating degree days (HDD) are defined as the sum of the differences between the daily average indoor and outdoor temperature. An indoor temperature of 21°C was assumed. The map is divided into five different regions: The two regions with HDD above 5000 Kd are not considered suitable for solar combi plus systems because there is not enough need for cooling. On the other hand in the region below 3000 Kd, there are some areas with extremely little heating demand which can also be excluded.

Come and visit us! Take a look at SOL ution Solartechnik GmbH www.sol-ution.com Gewerbestr.15 and you will find more A-4642 Sattledt information about the company and the solar Austria – Europe thermal systems SOLution can provide to you. SOL ution can also provide the following services to you: Technical support

Engineering of projects Figure 2 - Heating degree days in Europe Mounting of systems While the winter parameter (HDD) is a good figure for the Start up of systems heating needs of the building, the summer factor (CDD) can only be used for a first approximation because it does not take into account () and solar and internal

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gains, which in some cases contribute to a great extent to the Package System - SOLution cooling demand of a building. CDD are defined similarly to the SOLution offers absorption solar heating and HDD but with a reference indoor temperature of 26°C. cooling sets with a nominal chiller power of 15kW, 30 kW and 54kW (systems up to 200 kW upon request). Liquid sorbent: Lithium Bromide : Water

Example Chilled capacity 15 kW In 17°C

Out 11°C Flow rate 1.9 m³/h Figure 3 - Cooling degree days in Europe The map in Figure 3 shows again different zones across Europe. In the blue zones, there is not much cooling demand Hot water Thermal power 21 kW and for residential buildings this cooling demand can be In 90°C satisfied using technologies rather than active Out 80.5°C systems. However, also in these Central European locations Flow rate 2 m³/h solar combi plus systems may be suitable for buildings with high internal gains (e.g. office buildings) or existing buildings with high solar gains where passive measures are not feasible.

As can be expected, Southern European countries are better Cooling water Thermal power 35 kW suited for solar cooling systems than Central European climates In 30°C because of higher cooling demand and more available solar Out 36°C radiation. However, only locations that have also significant Flow rate 5 m³/h heating demand are ideally suited for solar combi plus systems because the solar thermal collectors can be used year around for both heating and cooling.

Thermal COP of the chiller 0.71 Electricity consumption 0.3 kW

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Suitable Collector Technology Residential Schematics There are several different collector technologies available on the market. Which technology is best suited for a particular application depends on the needed operation temperature. For solar combi plus systems, there are 4 relevant temperature levels: • 40°C for a low temperature space • 60°C for domestic hot water preparation • 70°C typical driving temperature for adsorption chillers • 90°C typical driving temperature for absorption chillers The efficiency curves of different collector models should now be compared at the highest necessary temperature level. Figure 4 shows efficiency curves for three collector technologies. Multi-unit Schematics 90%

80%

70%

60%

50%

40% Low temp.Low Spaceheating 30% FPC - high quality

Collector efficiency, % efficiency, Collector FPC - modest quality 20% DGC

10% ETC - qood quality Driving temp. Driving ETC - poor quality Driving temp. Adsortpionchiller Absortpion Absortpion chiller 0% DHW preparation 20 30 40 50 60 70 80 90 100

Operating temperature of collector, °C Please visit the ClimateWell website at www.ClimateWell.com Figure 4 - Typical collector efficiency curves based on aperture area of different collector types (FPC – Flat plate collector, DGC – Double glazed collector, ETC – for more information about our systems or contact us at Evacuated tube collector). Assumptions: 800 W/m² global radiation at normal [email protected] . incidence and an ambient temperature of 20°C.

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The first thing to notice is that there are very different qualities Package System - Climatewell on the market. The red and orange curves show a typical good ClimateWell’s Solar Cooling product combines the best features quality flat plate collector and a modest quality one of absorption and adsorption with its patented triple state respectively. For evacuated tube collectors the range of absorption technology. Among many features low electricity qualities is even larger. In between these technologies, double consumption, no noise, no crystallization problems and the glazed collectors have recently entered the market. Those are integrated storage capacity are some of the most important basically flat plate collectors with an additional glass cover or ones. Teflon foil to reduce heat losses from the collector. ClimateWell has offices in both Stockholm and Madrid and a manufacturing plant in Olvega, Spain.

Figure 5: Flat plate collectors (picture source: Sonnenklima) At low temperatures (as necessary for a low temperature space heating system) the differences in efficiency between the Within the Solarcombi+ project standard package solutions different collector technologies are relatively small (except for have been developed that will minimize the pre-engineering poor quality evacuated tube collectors which are not suitable efforts for each project and hence lower the overall system for this application). However, the more the operating costs. Some results from that work are shown on the next temperature increases the more important a good quality page. Further detailed information on ClimateWell package collector becomes. Evacuated tube collectors typically have the solutions can be found in Deliverable 4.4 on the project web smallest heat losses and are therefore best suited for high page. temperature applications. However, even among evacuated Different solutions were developed for different applications. tube collectors, it is important to pay attention to install a high The schematics below are suitable for small residential- and quality collector. On the other hand, good quality flat plate hotel applications respectively. collectors or double glazed collectors can in many cases almost keep up with evacuated tube collectors. It may be worth to

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Figure 13 – Solar cooling system installed on a roof in Granada Spain (picture source: IKERLAN)

Avoid Fossil Fuel Backup Figure 6: Evacuated tube collectors at Venice Marina System for Cooling (picture source: Climatewell) Other options to reduce fossil fuel consumption are to install a biomass or to use as heat backup system or an electrically driven compression chiller as cold backup. This will increase primary energy savings but also increase investment costs.

Figure 14 – Aerial view of solar

cooling system in Granada, Spain Figure 7: Double glazed flat plate collectors at the town hall / service center of (picture source: IKERLAN) the city of Gleisdorf, Austria (picture source: AEE INTEC)

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Use Chilled Ceiling Standard System Configurations Distribution Systems The following figures show two typical system configurations Chilled ceiling systems are more for small scale systems for solar heating, cooling and domestic favorable compared to fan coil hot water preparation. systems in terms of chiller The first configuration shown in Figure 8 has a central heat performance due to a higher storage tank with different temperature zones for space temperature level in the chilled heating, DHW preparation and driving heat for the chiller. This water circuit. However they are tank is heated by both the solar thermal collectors and the more expensive to install and auxiliary heater. For charging the store from the solar often more critical to use in Figure 11: Chilled ceiling collectors, there is a switching valve that allows drawing the heating mode for application in elements in a school in Butzbach, Germany (picture source: return flow to the collectors either from the middle or from the office and residential buildings. Fraunhofer ISE) bottom of the tank. This allows reaching the needed temperature level in the storage tank for driving the chiller more quickly. Loads

Heating

DHW

Collector Boiler Chiller

Cooling

Figure 12 - Solar heating and cooling system in a municipal administration building in Vienna, Austria (picture source: SOLution) heat rejection

Consider Solar Autonomous System for Cooling Source: Fraunhofer ISE To maximize primary energy savings it should always be Figure 8 - Typical system configuration with the auxiliary boiler charging the considered to design a system without backup for cooling in main heat storage tank summer. If a system is designed large enough, solar fractions Similarly, the return flow from the chiller or space heating loop for cooling can be above 90% and using the backup system for can be fed into the tank at different heights depending on its cooling can be avoided. temperature level.

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In summer time, energy is drawn from the tank to drive the Recommendations on System Design chiller. For the domestic hot water preparation, an external plate is used. In winter time the energy in the Following some recommendations for good design of solar storage tank is used for space heating and DHW preparation. combi plus systems are given based on the results of many simulations of different system configurations at different The configuration shown in Figure 9 is adapted to the Spanish locations across Europe that were carried out within the EU market where the auxiliary boiler is not allowed to charge the project SolarCombi+. solar heat storage tank. Therefore, the auxiliary boiler is connected in series to the solar heat storage tank. Loads Large Collector Areas Perform Best Heating Well-sized systems have a Boiler collector size of about 3.5 to DHW 5 m²/kW reference chilling capacity and a hot storage Collector Chiller volume of 50 to 75 l/m² collector aperture area. If the system is Cooling dimensioned according to this rule of thumb, high total solar fractions can be obtained and the system operates close to the heat rejection optimum in terms of primary Source: Fraunhofer ISE energy savings and the costs of Figure 10: 7.5 kW adsorption Figure 9 - Typical system configuration with auxiliary boiler connected in series these primary energy savings. chiller (picture source: SorTech) to solar heat storage tank

Implement Optimized Control Algorithm The control strategy influences the performance of the system considerable in terms of both solar fractions and primary energy consumption. That means that an individual adaptation of the system control to the chiller as a function of location, application and configuration offers significant potential for improvement. Especially the control of pumps and the heat rejection fan must be studied.

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